This section is intended to introduce various aspects of art that may be related to various aspects of the present disclosure described and/or claimed below, and to facilitate a better understanding of the various aspects of the present disclosure. It should be therefore understood that these statements are to be read in this light, and not as admissions of prior art.
The fluidic devices (e.g., medical devices) used nowadays usually incorporate micro-electro-mechanical (MEM) sensing elements. In such devices, the sensors are usually implemented by semiconductor structures, and the fluid flow path of the device and their connections with the fluid system, their packaging, and their mechanical/electrical interfaces are implemented by plastic fabrication techniques. In addition, electrical connectivity of such MEM devices with external systems is not implemented directly on the semiconductor die, and requires, inter alia, additional electrical interface involving wiring and electrical contacts, plastic structures, and printed circuit board (PCB).
These manufacturing techniques require accurate attachment and complex of the semiconductor die to its carrier to achieve electrical and mechanical connectivity to guarantee that pressure forces are correctly transmitted to the sensing elements, and obtain proper alignment between the fluid flow structures formed in the plastic packaging with the sensors and/or actuators implemented in the semiconductor die. This combination of manufacturing techniques typically results in a costly, and considerably complex, fabrication and integration of the fluidic MEM sensor (e.g., Silicon) into the fluidic devices.
Fluidic MEM devices fabrication techniques known from the patent literature are described in the following patent publications.
U.S. Pat. No. 7,311,693 describes a drug delivery device with a pressurized reservoir in communication with a flow path to an outlet. The flow path includes two normally-closed valves and a flow restriction. A pressure measurement arrangement measures a differential fluid pressure between two points along the flow path which span at least part of the flow restriction, one of the points being between the valves. A controller selectively opens the valves to deliver a defined quantity of the liquid medicament to the outlet.
U.S. Pat. No. 7,377,907 describes a portable insulin delivery device that supplies insulin in a pre-pressurized chamber, passes the insulin through a pressure-dropping labyrinth to a flow control valve. The valve is activated by a piezoelectric actuator. This allows for precise insulin delivery. An electronic package provides for programming of basal rates and bolus. A pressure sensor relays data concerning normal operation and pressure changes that indicate problems. The processor, keypad, displays power source, fluid pressure sensor and fluid flow control actuator are housed in a base unit. A removable cartridge unit houses the pre-pressurized fluid reservoir, flow path labyrinth, and flow control valve.
U.S. Pat. No. 7,318,351 describes a pressure sensor constructed of a plastic package. The plastic package incorporates in the same material a sensing diaphragm including tensile and compression regions. Deposited on the diaphragm are metal electrodes and a polymer film having piezoresistive properties. The electrodes and/or the polymer film are directly printed onto the plastic package without the use of a mask.
U.S. Pat. No. 7,375,404 describes a micro-electro-mechanical system (MEMS) device, along with means for its fabrication and operation for microfluidic and/or biomicrofluidic applications. The MEMS device includes a substrate, optional electrodes on the substrate, a patterned structure on the substrate, the patterned structure having a fluidic microchannel aligned with one or more of the optional electrodes, an encapsulation membrane covering the microchannel, and an optional reactive layer deposited over the electrode in the microchannel. MEMS devices of preferred embodiments permit a leak-tight seal to be formed around the microchannel and fluidic interconnects established for robust operation of fluidics-based processes. MEMS devices of other preferred embodiments permit reversible attachment and separation of the encapsulation membrane relative to the patterned structure.